The present invention, in some embodiments thereof, relates to kits and methods of differential staining of cervical cancer cells and/or tissues.
Cervical cancer is the second most common cancer in women worldwide and is a leading cause of cancer-related death in women in underdeveloped countries. Worldwide, it is estimated that approximately 473,000 cases of cervical cancer are diagnosed each year, with about 253,500 deaths per year.
Routine cervical cancer screening of the population by cervical vaginal smears has significantly decreased the incidence of cervical cancer in Western countries. In the United States, in 1998, about 12,800 women were diagnosed with cervical cancer and about 4,800 died from the disease. The incidence (7 new cases per 100,000 women per year) and mortality in the US are about half those for the rest of the world.
Epidemiological research conducted in 2003 in the central and western regions of China showed that cervical cancer is becoming a major health hazard for women in the countryside, with nearly 100,000 cases of cervical cancer being diagnosed annually, with approximately 20,000 deaths in 2001.
Cervical cancer develops in the lining of the cervix by gradual abnormal changes of cervix cells. Changes include low, intermediate or high-grade cervical intraepithelial neoplasia (CIN), low or high-grade squamous intraepithelial lesion (SIL), a condition that precedes cervical cancer, carcinoma in situ or invasive carcinoma. Invasive cervical cancer includes about 80% of squamous cell carcinomas (SCC) and about 20% of adenocarcinomas.
Cervical vaginal smears are scrapings from the female reproductive tract aimed at enabling the diagnosis of numerous types of atypia, some of neoplastic nature, others of pre-malignant nature, or other pathological processes. All types of cellular samples must be transferred to a slide, processed and stained in order to enable visualization by means of light microscopy.
At present, diagnostic cytology is typically based on a rather narrow set of staining methods and compositions such as alcohol-fixed Papanicolaou stain and the air-dried May-Grunwald-Giemsa (a version of which is known as Romanowsky) stain, while staining with hematoxylin and eosin, Shorr's staining for endocrine cytology and the Pappenheim method are more rarely used.
The Papanicolaou staining method was initially developed for analysis of vaginal smears [Papanicolaou and Traut, Am. Y. Obst. Gynecol. (1941) 42:193-206; Papanicolaou “Atlas of Exfoliative Cytology” Cambridge, Mass.: Harvard University Press (1954)] and allows the differentiation of cell types of stratified and simple epithelia present in alcohol-fixed smears, with a detailed morphology of the nucleus and cytoplasm in normal and tumor cells. However, the Papanicolaou staining procedure, as well as all other cytological staining procedures, does not reveal any tinctorial selectivity for malignant cells, and the assessment of pathologically relevant traits is performed by means of interpretation of cellular morphology, which usually requires highly qualified and experienced cytopathologists.
The classical cytological techniques are in many cases supplemented by a group of technologies, which are based on compounds of high affinity and specificity, known as immunohistochemistry, immunocytochemistry or in situ hybridization. These technologies are used for detection of tumor markers of prognostic value (e.g., the p16INK4A and p14ARF markers, p16 protein), as well as the detection of other oncogenic expression features and nucleic acid sequences.
PCT Publication No. WO2007/102146 discloses a method of staining or pre-staining cells using an extract of a Ficus elastica plant, or active ingredients thereof, for the diagnosis of cancer or metabolic diseases.